A disc drive is an example of a data storage system that uses magnetic fields for writing and reading data. Transducers write information to and read information from data surfaces of the discs. In one example, transducers include a recording or write head for generating a magnetic field that aligns the magnetic moments of a magnetic medium to represent desired bits of data. Magnetic recording heads include both longitudinal and perpendicular recording techniques. Perpendicular recording is a form of magnetic recording in which magnetic moments representing bits of data are oriented perpendicularly to the surface of the recording layer. Perpendicular magnetic write heads typically include main and return poles that are separated to form a write gap and extend from pole tips located at an air-bearing surface (ABS) to a back gap region. A coil is included to generate magnetic signals through the main and return poles in response to a current conducted through the coil. The main pole tip focuses the magnetic flux density such that the magnetic fields interact with the magnetic medium to orient its magnetic moments in an up or down direction.
As the desire for higher data rate and higher data density increases in magnetic memory storage, great challenges are placed on magnetic write head design.